Anastomosis is the connection of two tubular structures or organs. It refers to connections between blood vessels or between other tubular organs such as loops of intestine. Circulatory anastomosis is further divided into arterial and venous anastomosis. An example of surgical anastomosis occurs when a segment of intestine is resected and the two remaining ends are sewn or stapled together (anastomosed), for example Roux-en-Y anastomosis is an intestinal anastomosis procedure. Connecting blood vessels in humans and mammals is a frequently performed procedure. This includes the treatment of peripheral vessel diseases, congenital or developmental deformities and trauma.
Anastomosis is most commonly carried out by a skilled surgeon using sutures to hold the two tubular organs together. Thus, for vascular anastomosis, the surgeons perform each anastomosis by hand suturing with a tiny, curved needle and very fine suture filament. Such a suturing method, however, is very time consuming, even for an experienced surgeon. In some cases the blood flow in the newly joined vessels may be poor, and the surgeon must remove the stitches and repeat the suturing procedure. In some surgical procedures, the total time required for suturing is very substantial, increasing ischemia time and/or resulting in prolonged anaesthesia time and increasing the cost of the surgical procedure.
For end-to-side type grafting procedures the surgeon attaches the open end of a graft vessel to the side of a target vessel. In a preferred type of suturing method for end-to-side anastomosis of blood vessels, the surgeon passes a needle through the wall of the first vessel (such as the coronary artery) from the inside to the outside, and then passes it from the outside to the inside of the second vessel (such as the graft vessel), so that when the suture is drawn tight, the inside walls of the vessels come together, intima-to-intima. This ensures that the vessels heal together properly with a smooth layer of endothelial cells formed on the inside of the anastomosis. The surgeon typically places a single stitch in this manner at each of the heel and toe locations of the anastomosis, and then makes a running stitch on each half of the anastomosis between the heel and toe.
Surgeons commonly use an end-to-end type of anastomosis for joining together larger hollow organs such as bowel, and for some heart bypass procedures where the arterial flow is completely occluded by stenosis in a diseased artery. End-to-end type anastomosis is also used in microsurgical procedures (microvessel (<3 mm) anastomosis)—such as when replacing severed limbs or fingers or in autologous free tissue transplantation or composite tissue allografting etc.
In recent years, surgeons have been using alternative, minimally-invasive means of access to reduce the size of the surgical wound created. In such procedures, the surgical opening and visibility are significantly reduced, and hand suturing is more difficult. Other new developments in surgical procedures have made conventional suturing even more difficult. For example, some surgeons now perform bypass surgery on beating hearts to avoid the complications associated with using a heart lung bypass machine.
The literature contains disclosures of a number of devices for augmentation of suturing techniques. These devices attempt with varying degrees of success to reduce the difficulty in repeatedly passing a needle and thread through organ walls. However, the main disadvantage of using sutures remains that the success and thus patency rate of the procedure is directly related to the skills and dexterity of the surgeon. Also, the smaller the vessels are that need to be connected the more time consuming the procedure is. As long as microsurgery and free flap surgery in reconstructive procedures are time-consuming and dependent on technical skills, they will never be very popular.
For many years, many different attempts have been made to provide an apparatus that would allow end-to-end (and/or end-to-side) anastomosis of tubular organs without the use of sutures (i.e. suturelessly).
Some success has been achieved in this area with relatively large tubular organs such as the intestines, for which bowel staplers have been developed (see, for instance, U.S. Pat. No. 5,172,845). However such stapling devices are not generally suitable for use with much smaller and/or much more sensitive vessels such as blood vessels.
Another approach to end-to-end anastomosis has been to provide a tubular prosthesis to which each end of the two tubular organs are joined (see, for example, U.S. Pat. No. 4,728,328).
Also, in some prior art systems, a tubular element may be inserted into each end of the two tubular organs to be joined and the tubular organs may be fastened onto the tubular element (see, for example, U.S. Pat. No. 2,127,903, WO 2007/131189 and US 2004/0230209). If used in such a way that the ends of the vessel heal to one another (e.g. when joining using sutures around such a tubular element), it has been suggested that such a tubular element might be made from a bioresorbable material (e.g. U.S. Pat. No. 2,127,903). Disadvantages of such systems include the fact that the interior diameter available for flow of body fluids (e.g. blood) is reduced by the tubular element. Such a diameter-reduction can be material when anastomosing relatively small vessels. Also, in such prior art systems, the tubular element is within the flow-path of the vessel and must therefore have suitable, very-hard-to-achieve biocompatibility material properties to prevent its causing further medical problems for the patient (e.g. for blood vessels, such effects might include creating emboli that could migrate into the systemic circulation.
U.S. Pat. No. 4,593,693 and US 2005/0182430 disclose a different approach in which a ring element is provided that, in use, remains at all times outside of the flow-path of the tubular organs. In this approach, an end of a first tubular organ to be joined is threaded through the ring element, folded back on itself and hooked onto radially-outwardly projecting spikes on the ring element, which are provided for this purpose. An end of a second tubular organ to be joined is then pulled over the ring element and hooked over the same spikes. This methodology thus creates desirable intima-to-intima contact of the organs being joined and keeps the ring element itself out of the flow-path of the vessels. The ring element also acts as an external tubular scaffold—holding the vessels open at the joint, though remaining outside of the vessels at all times. However, this system has a number of disadvantages including that, over time, the spikes may cause undesirable internal damage to other organs of the patient near to the anastomosis joint—particularly in bodily locations where many small delicate organs are very close to each other and often in motion (e.g. blood vessels in a finger). Also, for vessels that may be in motion when in use, there is a risk that a vessel may become unhooked and, at best, cause a need to repeat the surgical procedure. Another disadvantage of the ‘hooked on’ system is that unintended leakage may occur at the joint prior to full healing and, depending on the particular type and location of the particular vessels, this may cause considerable undesirable patient complications.
Still another approach is disclosed in EP 1 842 495, which, to the best knowledge of the inventors of the present application, represents the only sutureless anastomosis system that has ever become available on the open market. In this system, two rings with axially directed metal spikes are connected, each to the end of one of the two tubular organs to be anastomosed. A rather complex applicator device is then used to mechanically force the two rings together such that the spikes of each ring engage and lock into place the other ring. Although this system has enjoyed a certain amount of clinical success, it has several disadvantages including the continued use of spikes as outlined above and the fact that the form and size of the applicator device can make it difficult to make the joint in applications providing tight environments. Also, the relatively large dimensions of the rings makes it prone to tip over and thereby constrict or compress the vessel.
It is an objective of the present invention to provide an anastomosis kit and method that allows sutureless anastomosis and overcomes some of the disadvantages of prior art systems.